pinctrl: add function to parse generic pinconfig properties from a dt node

pinconf_generic_parse_dt_config() takes a node as input and generates an
array of generic pinconfig values from the properties of this node.

As I couldn't find a mechanism to count the number of properties of a node
the function uses internally an array to accept one of parameter and copies
the real present options to a smaller variable at its end.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 81 insertions, 0 deletions

diff --git a/drivers/pinctrl/pinconf-generic.c b/drivers/pinctrl/pinconf-generic.c
index 9a6812b50a32..d3c693c0c250 100644
--- a/drivers/pinctrl/pinconf-generic.c
+++ b/drivers/pinctrl/pinconf-generic.c
@@ -21,6 +21,7 @@
 #include <linux/pinctrl/pinctrl.h>
 #include <linux/pinctrl/pinconf.h>
 #include <linux/pinctrl/pinconf-generic.h>
+#include <linux/of.h>
 #include "core.h"
 #include "pinconf.h"
 
@@ -139,3 +140,83 @@ void pinconf_generic_dump_config(struct pinctrl_dev *pctldev,
 }
 EXPORT_SYMBOL_GPL(pinconf_generic_dump_config);
 #endif
+
+#ifdef CONFIG_OF
+struct pinconf_generic_dt_params {
+        const char * const property;
+        enum pin_config_param param;
+        u32 default_value;
+};
+
+static struct pinconf_generic_dt_params dt_params[] = {
+        { "bias-disable", PIN_CONFIG_BIAS_DISABLE, 0 },
+        { "bias-high-impedance", PIN_CONFIG_BIAS_HIGH_IMPEDANCE, 0 },
+        { "bias-bus-hold", PIN_CONFIG_BIAS_BUS_HOLD, 0 },
+        { "bias-pull-up", PIN_CONFIG_BIAS_PULL_UP, 0 },
+        { "bias-pull-down", PIN_CONFIG_BIAS_PULL_DOWN, 0 },
+        { "bias-pull-pin-default", PIN_CONFIG_BIAS_PULL_PIN_DEFAULT, 0 },
+        { "drive-push-pull", PIN_CONFIG_DRIVE_PUSH_PULL, 0 },
+        { "drive-open-drain", PIN_CONFIG_DRIVE_OPEN_DRAIN, 0 },
+        { "drive-open-source", PIN_CONFIG_DRIVE_OPEN_SOURCE, 0 },
+        { "drive-strength", PIN_CONFIG_DRIVE_STRENGTH, 0 },
+        { "input-schmitt-enable", PIN_CONFIG_INPUT_SCHMITT_ENABLE, 1 },
+        { "input-schmitt-disable", PIN_CONFIG_INPUT_SCHMITT_ENABLE, 0 },
+        { "input-schmitt", PIN_CONFIG_INPUT_SCHMITT, 0 },
+        { "input-debounce", PIN_CONFIG_INPUT_DEBOUNCE, 0 },
+        { "power-source", PIN_CONFIG_POWER_SOURCE, 0 },
+        { "slew-rate", PIN_CONFIG_SLEW_RATE, 0 },
+        { "low-power-mode", PIN_CONFIG_LOW_POWER_MODE, 0 },
+        { "output-low", PIN_CONFIG_OUTPUT, 0, },
+        { "output-high", PIN_CONFIG_OUTPUT, 1, },
+};
+
+/**
+ * pinconf_generic_parse_dt_config()
+ * parse the config properties into generic pinconfig values.
+ * @np: node containing the pinconfig properties
+ * @configs: array with nconfigs entries containing the generic pinconf values
+ * @nconfigs: umber of configurations
+ */
+int pinconf_generic_parse_dt_config(struct device_node *np,
+                                    unsigned long **configs,
+                                    unsigned int *nconfigs)
+{
+        unsigned long cfg[ARRAY_SIZE(dt_params)];
+        unsigned int ncfg = 0;
+        int ret;
+        int i;
+        u32 val;
+
+        if (!np)
+                return -EINVAL;
+
+        for (i = 0; i < ARRAY_SIZE(dt_params); i++) {
+                struct pinconf_generic_dt_params *par = &dt_params[i];
+                ret = of_property_read_u32(np, par->property, &val);
+
+                /* property not found */
+                if (ret == -EINVAL)
+                        continue;
+
+                /* use default value, when no value is specified */
+                if (ret)
+                        val = par->default_value;
+
+                pr_debug("found %s with value %u\n", par->property, val);
+                cfg[ncfg] = pinconf_to_config_packed(par->param, val);
+                ncfg++;
+        }
+
+        /*
+         * Now limit the number of configs to the real number of
+         * found properties.
+         */
+        *configs = kzalloc(ncfg * sizeof(unsigned long), GFP_KERNEL);
+        if (!*configs)
+                return -ENOMEM;
+
+        memcpy(*configs, &cfg, ncfg * sizeof(unsigned long));
+        *nconfigs = ncfg;
+        return 0;
+}
+#endif